The Morphological Characteristics of the First Stage of Rice Panicle Development

Comparing the morphology of the first bract and flag leaf primordium by binocular dissecting micro scope and scanning electronic microscope (SEM), no any difference is observed. The prevailing views that first bract holds an obtuse angle (the angle between the first bract and axis of apical cone is larger than 90°)is not true,and that when the first bract primordium appears the flag leaf primordium does not grow over the apical cone is not true too. These mistakes are caused by neglecting the fact that there are at least two kinds of leaf number of main culm (n and n-1)in the same variety and the same plot. The name of the first stage of panicle development should be changed into bracts differentiating stage. The beginning of this stage is the appearing of the 1st and 2nd bract primordium(Fig. 4 6). Then,the third,fourth...bract primordium follows until the primary branch primordium appears. The appearing of primary branch primordium starts the second stage of panicle development (Fig. 5). This conclusion makes the discriminating standard of the beginning feature of 8 stages of rice panicle development to be practicable.